arm64: dts: mediatek: mt7981b-openwrt-one: Enable SPI NOR

The openwrt one has a SPI NOR flash which from factory is used for:
* Recovery system
* WiFi eeprom data
* ethernet Mac addresses

Describe this following the same partitions as the openwrt configuration
uses.

Signed-off-by: Sjoerd Simons <sjoerd@collabora.com>
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>

arch/arm64/boot/dts/mediatek/mt7981b-openwrt-one.dts

@@ -3,6 +3,7 @@
 /dts-v1/;
 
 #include "mt7981b.dtsi"
+#include "dt-bindings/pinctrl/mt65xx.h"
 
 / {
 	compatible = "openwrt,one", "mediatek,mt7981b";
@@ -22,6 +23,84 @@
 	};
 };
 
+&pio {
+	spi2_flash_pins: spi2-pins {
+		mux {
+			function = "spi";
+			groups = "spi2";
+		};
+
+		conf-pu {
+			bias-pull-up = <MTK_PUPD_SET_R1R0_11>;
+			drive-strength = <8>;
+			pins = "SPI2_CS", "SPI2_WP";
+		};
+
+		conf-pd {
+			bias-pull-down = <MTK_PUPD_SET_R1R0_11>;
+			drive-strength = <8>;
+			pins = "SPI2_CLK", "SPI2_MOSI", "SPI2_MISO";
+		};
+	};
+};
+
+&spi2 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&spi2_flash_pins>;
+	status = "okay";
+
+	flash@0 {
+		compatible = "jedec,spi-nor";
+		reg = <0>;
+		spi-max-frequency = <40000000>;
+		#address-cells = <1>;
+		#size-cells = <1>;
+
+		partitions {
+			compatible = "fixed-partitions";
+			#address-cells = <1>;
+			#size-cells = <1>;
+
+			partition@0 {
+				reg = <0x00000 0x40000>;
+				label = "bl2-nor";
+			};
+
+			partition@40000 {
+				reg = <0x40000 0xc0000>;
+				label = "factory";
+				read-only;
+
+				nvmem-layout {
+					compatible = "fixed-layout";
+					#address-cells = <1>;
+					#size-cells = <1>;
+
+					wifi_factory_calibration: eeprom@0 {
+						reg = <0x0 0x1000>;
+					};
+
+					wan_factory_mac: macaddr@24 {
+						reg = <0x24 0x6>;
+						compatible = "mac-base";
+						#nvmem-cell-cells = <1>;
+					};
+				};
+			};
+
+			partition@100000 {
+				reg = <0x100000 0x80000>;
+				label = "fip-nor";
+			};
+
+			partition@180000 {
+				reg = <0x180000 0xc80000>;
+				label = "recovery";
+			};
+		};
+	};
+};
+
 &uart0 {
 	status = "okay";
 };

arch/arm64/boot/dts/mediatek/mt7981b.dtsi

@@ -156,7 +156,7 @@
 			status = "disabled";
 		};
 
-		spi@11009000 {
+		spi2: spi@11009000 {
 			compatible = "mediatek,mt7981-spi-ipm", "mediatek,spi-ipm";
 			reg = <0 0x11009000 0 0x1000>;
 			interrupts = <GIC_SPI 142 IRQ_TYPE_LEVEL_HIGH>;